1. Field of the Invention
The present invention relates to a column shift device for an automatic transmission, and particularly, to an improvement in a column shift device for an automatic transmission, including a bracket mounted to a steering column, a shift piece connected to the bracket through a first pivot for turning movement to any of a plurality of shift positions, a shift lever which is connected to the shift piece through a second pivot disposed on a plane substantially perpendicular to the first pivot and which is capable of turning the shift piece through the second pivot, a shift restraining mechanism which is provided on the bracket for engagement and disengagement permitted in response to a swinging movement of the shift lever about the second pivot and adapted to restrain a turning movement of the shift lever about the first pivot during engagement of the shift restraining mechanism, and a shift link which is carried on the bracket for swinging movement and is operated in association with the turning movement of the shift lever about the first pivot to control the automatic transmission.
2. Description of the Related Art
In a conventional column shift device of this type, when the shift lever and the shift link are operatively connected to each other, a joint member is oscillatably mounted at a tip end of an arm shaft projectingly provided on the shift piece, the joint member being put into engagement in a radial guide groove defined in the shift link for sliding movement in longitudinal and depth-wise directions of the groove(for example, see Japanese Patent Application Laid-open No. 8-282317).
In such a conventional column shift device, the joint member is secured to the tip end of the arm shaft and hence, if the arm shaft is turned through an angle .theta., as shown in FIG. 15, the joint member provides the turning movement of the shift link while describing a locus of an arc a. Therefore, the turning stroke provided to the shift link by the joint member, i.e., the shift stroke of a manual valve of the automatic transmission is equal to the length S.sub.1 of a chord of the arc a. Thereupon, when the turning stroke of the shift link is increased, the turning angle .theta. of the arm shaft is obliged to be increased. However, such an increase is limited to a certain extent for ensuring a good manipulatability.